Piston type respirator



Dec. 28, 1965 E. T. MORCH 3,22

PISTON TYPE RESPIRATOR Filed Dec. 30, 1959 7 Sheets-Sheet l INVENTOR.

E. T. MGRCH PISTON TYPE RESPIRATOR Dec. 28, 1965 7 Sheets-Sheet 2 FiledDec. 30, 1959 QQN Ill

. A INVENTOR.

@6121 jydf'fi Dec. 28, 1965 E. T. MoRcH rzswon TYPE RESPIRATOR 7Sheets-Sheet I5 Filed Dec. 30, 1959 Dec. 28, 1965 Filed Dec. 30, 1959 E.T. MORCH PISTON TYPE RESPIRATOR '7 Sheets-Sheet 4 INVENTOR.

Dec. 28, 1965 E. T. MORCH PISTON TYPE RESPIRATOR 7 Sheets-Sheet 5 FiledDec. 30, 1959 1 INVENTQR. E7252 hierj ibrcfi E. T. MQRCH PI STON TYPERESPIRATOR '7 Sheets-Sheet 6 INVENTOR. rzzsZYfzr/Vo'fai BY g M Dec. 28,1965 Filed Dec. 50, 1959 United States Patent 3,225,758 PISTON TYPERESPIRATOR Ernst Trier Miirch, 5816 Blackstone Ave., Chicago, Ill. FiledDec. 30, 1959, Ser. No. 862,869 17 Claims. (Cl. 128-29) The presentinvention relates, in general, to respirators, and in particular to newand improved respirator means for use on humans suffering disabilitiesof the human respiratory system, e.g., polio cases and accident casesinvolving critically crushed chests.

In my application for United States patent, Serial No. 573,514, entitledRespirator, filed March 23, 1956, now Patent 2,969,879, issued January31, 1961, I have disclosed respirator means which automatically producespositive and negative pressures in the lungs of a patient tosubstantially duplicate any respiratory condition and to exert completecontrol over the patients respiration when necessary. This machine, asdisclosed and claimed in my copending application, is particularlydesigned for use during surgery, especially thoracic operations. Undersuch conditions, respiration can be assisted and controlled, and theproblems of thoracic surgery are in the hands of a team trained in theseproblems and constantly aware of the possible rapid changes incardio-pulmonary dynamics.

My present invention, however, has an advantage over the respiratordisclosed and claimed in my copending application, and over other priorart respirators, in that it is capable of handling thoracic injuriesoccurring at -in dustrial sites or on highways far from medical centers.It is also capable of handling respiratory difiiculties during thoracicsurgery, as well as respiratory difiicul-ties due to infections, such aspoliomyelitis, muscle disease-s, trauma to the brain, and head injuries,post-operative neurosurgical conditions, cerebral vascular accidents,respiratory depression (industrial poisons, suicide, overdosage ofmedications, and anesthetics), and in ventilatory insufficiencyfollowing pulmonary resection.

The general principle of treatment of these respiratory difficultieswill be explained hereinafter once the mechanical features of myrespirator are explained.

It can be seen that, in view of the applicability of my respirator forhandling thoracic injuries at industrial sites and the like, as Well asfor its use in medical centers, it is of particular importance that mypresent invention be constructed small and compact, so that it will fitunder any normal hospital bed and be readily transported, that it berugged in construction, simple to operate, clean and assemble, and thatit be operable without special knowledge or tools.

These are accomplished by my respirator and form some of the featuresand objects of my present invention.

More particularly, it is an object of this invention to provide animproved respirator that operates entirely on the principle of volumecontrol, not on a pressure principle, and that also includes means forcontrolling the rate of respiration.

Briefly, my invention comprises a piston type pump driven by an electricmotor and so constructed and arranged as to give a large stroke volume.The stroke volume of my invention is adjustable so as to regulate thepulsations of air or air-gas mixture directed to the patient. Pump speedis also adjustable to regulate the rate of the pulsations. Fresh air,air-oxygen, carbondioxide-oxygen mixture or other gas mixture, is pumpedaccording to my invention through a humidifier into an exhalator valveand thence into a face mask, endotracheal tube, or tracheostomy tube.Also, according to my invention, an exhalator valve is interposed nearthe mask or tube and so constructed and arranged as to provide 3,225,758Patented Dec. 28, 1965 proper timing, i.e., the proper pressure profileof gas, for optimal ventilation of the patient.

My exhalator valve is constructed and arranged to parts, like parts ofwhich are inter-changeable, and to make the valve substantiallysymmetrical in various of its parts, so that little skill and no specialtools are required to disassemble the device for cleaning and toreassemble the same. This, too, is an important feature of my invention.

My machine is so constructed and arranged that mechanical failures arenegligible, and a hand pump has been incorporated so that ventilation ofthe patient can be carried out in case of electrical power failure, orwhen transporting the patient, as by ambulance, aircraft, etc. This handoperability also forms a very important object of my invention in viewof the fact that it can be used at industrial sites and duringtransport.

Other important features of my invention are the incorporation thereinof safety means so that gas humidifying liquid will not flow to thepatient, regardless of the careless handling and/ or the position of thedevice, of means for controlling the stroke and the rate ofreciprocation of the piston, which means are operable without stoppingthe machine, and of safety means in the gas circuit for preventinginsufficient or excessive supply of gas to the patient despite carelesshandling of the gas supply, such as oxygen tanks and the like.

Further important features of my invention are the use of a standardcommercially available motor and gear reduction box, the utilization ofjust two simple controls for controlling the rate and volume of gassupply, the provision of a construction such that no special tools ormechanical knowledge are required in normal use of the machine, and theprovision of a hand pump that will operate at any phase of the stroke ofthe main pump in event of failure thereof.

Other and more particular objects and advantages of my invention will beapparent to those skilled in the art from the following description anddrawings forming a part hereof and wherein:

FIGURE 1 is a perspective view illustrating a respirator meansconstructed in accordance with the teachings of my invention and showingits compactness and its capability of being pushed under most hospitalbeds so that it does not occupy any functional floor space;

FIGURE 2 is a plan view illustrating the internal arrangement of oneembodiment of my respirator means;

FIGURE 3 is a side view, partly in section and partly in elevation, ofmy respirator, the view illustrating the variable speed power source forthe piston pump forming a part of my respirator;

FIGURE 4 is a fragmentary horizontal section illustrating a hand pumparrangement forming part of my respirator and usable in the event thatthe power source illustrated in FIGURE 3 is rendered inoperative or therespirator is being transported;

FIGURE 5 is a fragmentary vertical section, on an enlarged scale,illustrating the piston pump and the means for varying the strokethereof;

FIGURE 6 is a vertical cross-section of my respirator, the viewparticularly illustrating the stroke regulating means;

FIGURE 7 is a cross-sectional view taken substantially on line 7-7 ofFIGURE 2 and illustrating the end wall and the intake and exhaust valvesof the pump;

FIGURE 8 is a fragmentary sectional view illustrating in further detailthe means for admitting air to the pump;

FIGURE 9 is a fragmentary sectional view of the means for introducingwater into the humidifier and of the means for causing the gas pumped bythe respirator to pass through the humidifier;

FIGURE is a vertical section of one embodiment of the exhalator valveforming part of my invention;

FIGURE 11 is a fragmentary vertical section of another embodiment of myexhalator valve;

FIGURE 12 is a schematic representation of the action of ribs broken inseveral places during active (patients) respiration;

FIGURE 13 is a schematic representation of the action of broken ribsduring passive respiration under the direction and control of myrespirator means; and

FIGURE 14 is a diagram of the pressure profile of my respiratory means.

Referring to the drawings, and particularly to FIGURE 1, I haveillustrated my invention in connection with a normal hospital bed B toshow the size and adaptability of one embodiment thereof. It can be seenthat my respirator means, indicated in its entirety as R, with itsexhalator valve E, is relatively small and compact and will normally fitunder an average hospital bed. Exhalator valve E is in communicationwith a tracheostomy tube T (or an endotracheal tube or a face mask). Itmay therefore be placed where it will not be an obstruction to thenecessary medical and nursing staff, and with this arrangement thepatient can be cared for and examined, even though the patient isincapable of normal or active respiration. It can also be seen that myinvention obviates tractions normally required in cases of chestinjuries, and that it also obviates the necessity for iron lungs inpolio cases. Obviously, tractions, iron lungs and the like, makeexamination and normal care by the hospital staff difiicult, if notimpossible, and their obsolescenece by my invention also is an importantfeature thereof.

Turning now more particularly to the details of my respirator means,attention is directed to FIGURES 2 and 3. My respirator means comprises,generally, a base 10 provided with three upright side walls 11, 12, 13,a hinged side or end wall 14, and a hinged top cover 15, the latter ofwhich is preferably transparent. The purpose of the hinged wall 14 willbe explained in detail hereinafter. On the bottom of the base 10 aresuitably mounted conventional castor wheels 16, and the base 10 isprovided with a hinged handle 17, for conveniently transporting therespirator.

Within the four walls 11-14, I have provided an electric motor 18 and avariable speed drive 19, the output shaft 20; of which is connected to astroke regulating means, indicated in its entirety at 21. The motor 18and variable speed drive means 19 are readily available commercially,and the latter may be of the type described and shown in US. Patent No.2,535,409 to L. A. Graham, issued Decemher 26, 1950.

Also on side wall 13 I have provided suitable electric supply andcontrol means including connection boxes 22 for connecting motor 18 to asource of electric power, a switch 22a to control the supply of currentto the motor, and convenience outlets 23 so that, where desired, mydevice will provide outlets for other devices.

The stroke regulating means 21 is a variable crank, and as more clearlyshown in FIGURES 2, 5 and 6, comprises a T-shaped arm 24 having its mainleg 25 fixedly attached to the shaft 20 and having its cross member orarm 26 internally bored. At its ends the cross arm is counterbored toreceive a pair of bearing means of any conventional type, illustrated at30 and 31. These bearing means journal a screw 32, having a frictionwheel 33 affixed to one end thereof outwardly of the arm 26. R0- tationof the friction wheel 33 will cause rotation of the screw 32 which inturn causes movement of a piston rod carrier or cam 34. Cam 34 issuitably internally threaded so as to mate with the threads of the screw32 and ride thereon. The arm 26 is suitably slotted, as indicated at 35,for reception of an extension 36 on the cam 34, whereby the cam is heldagainst rotation and is caused to be moved radially of the shaft 20 whenthe screw 32 is rotated. The extension 36 of the cam 34 is in turnpivotally connected to a piston rod 37 in any suitable manner, as by abolt 38 secured to the extension 36 and defining a crank pin for therod.

From the above description it will be appreciated that upon rotation ofthe T-shaped member 24 by the variable speed drive shaft 20,reciprocating motion is imparted to the piston rod 37 by reason of thefact that its connection to the T-shaped member 24 is eccentric to theaxis of rotation of the shaft 20. Piston rod 37 is suitably connected toa piston 40 later to be described in detail. It is important to notethat the T-shaped arm 24, the piston rod 37 and the connections thereofare relatively thick and heavy so that if such items as bottles,glasses, or the like were accidentally dropped into the device when thecover was removed, the arm would crush the same without stopping; themotor and drive being powerful enough to do this. It is also importantto note that while the variable speed drive shaft 20 is rotating, therpm. of the shaft 20 may be changed in a conventional manner through thecontrol knob 41 as explained in more detail in the aforementionedpatent. Also, it is the object of this invention to accommodatevariation in the stroke of the piston rod 37 and piston 40 while themachine is in operation.

In the latter respect, the wheel 33 has its peripheral surface coveredwith a suitable friction material, such as rubber, and it can be seenthat, upon rotation of the arm 24, the wheel orbits to define a circle.At the lower segment of this defined circle, I have provided a pair ofsegments 42 and 43. These segments are plates corresponding toapproximately one-half of the circle defined by the wheel 33 orbitingabout the shaft 20 and are adapted to be alternately engaged to saidwheel.

The segments 42, 43 are each provided with a downwardly extending arm44, 45 which extends through a suitable aperture in the base 10. Theseextensions or arms 44, 45 are suitably attached as by screws 47 to across bar 46 which serves to space the segments 42, 43 from each other adistance slightly greater than the diameter of the wheel 33, and todispose the segments to opposite sides of the orbital path of the wheel.This spacing permits the wheel 33 to orbit about the shaft 20 withoutnormally engaging either segmental plate 42 or 43. Bar 46 is providedcentrally thereof with a shaft 50 extending parallel to the planes ofthe extensions 44 and 45. The shaft 50 is journalled in the dependingarms. of a pair of angle irons 51 and 52 which are secured to the lowerside of the base 10 to opposite sides of the aperture through which theextensions 44 and 45 project. The angle irons 51 and 52, with shaft 50and bar 46,. thus serve to hold the segment plates 42, 43. The shaft; 50is flattened at one end, as at 53, and is disposed between a pair ofleaf springs 54, 55. The flattened portion 53 provides a camming actionwith respect to the leaf springs 54, and the springs provide means forretain-- ing the segments 42 and 43 in their normal position spaced toopposite sides of the orbital path of the wheel 33. Movement of theplates 42 or 43, in one direction or another, will cause the shaft 50 torotate about its axis, spreading the leaf springs 54, 55, with theresult that the springs will return the plates 42, 43 to their normalposition upon release of the plates.

Springs 54 and 55 are suitably apertured at their ends to receive aspring retaining and adjusting means in the form of bolts 56 and nuts 57attached to the base plate 10. On the opposite sides of the extensions44 and 45, I have provided suitable adjusting mechanism in the form ofset screws 58 and 59, the purpose of which is to regulate the maximummovement of the plates 42, 43. As can be seen in FIGURES 5 and 6, one ofthe segments (42 as shown) is provided with an arm 60 which extendsupwardly substantially midway of the top cover 15, the latter beingprovided with an aperture 61 through which the arm 60 may be operated.

It can be seen from FIGURE 6 that movement of the arm 60 to and fro willselectively cause the segments 42 and 43 to be moved into the orbitalpath of movement of the wheel 33, whereby the segments will beselectively engaged by the peripheral surface of the rotatablefrictional wheel 33, thereby to rotate the Wheel and the screw 32. Thislatter, in turn, changes the position of the connection of the pistonrod 37 relative to the axis of rotation of the shaft 20 and, of course,this will change the stroke of the piston 40. By moving one segment intothe path of the wheel, the cam 34 is caused to move radially outwardlyof the shaft 20 to increase the stroke. By moving the other segment intothe path of the wheel, the cam is caused to move radially inwardly todecrease the stroke of the piston. In either case, the wheel engages thesegment only during approximately one-half of its orbital time, therebyto facilitate precise control over the stroke of the piston and theoutput volume of the pump.

It is important to note that I have so constructed and arranged mystroke regulating means as to permit variation of the stroke of thepiston 40 and hence the volume of the output of the pump while therespirator is in operation. This, with the variable speed transmissionwhich may be changed while the respirator is in operation, assures wideadaptability of my device for use clinically.

Turning now to FIGURES 5 and 7, where I have illustrated my piston pumpin more detail, it can be seen that the pump comprises the previouslyidentified piston rod 37 and piston 40, the latter reciprocating in acylinder 62 and being provided with piston rings 63 (three shown) of anysuitable material, such as nylon, Teflon, and the like. A pair of plates64 and 65, each having a circular groove 66 and 67 to respectivelyreceive the ends of the circular cylinder 62, form end walls for thepump and are suitably attached to the base 10. Plate 65 forms the endwall for the pumping chamber 68. End wall 64 is vertically slottedcentrally thereof to permit the reciprocation of the piston rod 37 andserves to support the cylinder 62 (FIGURE 5). The other end plate 65, inaddition to being an end plate which supports the opposite 'end of thecylinder 62 and defines a part of the pumping chamber 68, is providedwith an inlet and outlet to the pumping chamber, as will now bedescribed.

As more clearly illustrated in FIGURES 4 and 7, end plate 65, within theperiphery of the groove 67, is bored to provide a centrally locatedoutlet 71 and an inlet 72. In the embodiment illustrated, the inlet 72is located near the top of the end plate 65 and communicates with ahorizontally extending bore 73. At one end of this horizontallyextending bore 73, I have provided an inlet 74 for air, or air-oxygenmixture, and an inlet 75 for oxygen, both of which operate through aconventional spring or gravity biased one-way inlet valve, indicated inits entirety at 76. The inlet valve 76 preferably comprises a ball 77, aspring biasing means 78, and a threaded cap 80, which is received in thethreaded bore 81; the latter serving as a means for regulating thecompression of the spring. Thus, on the intake stroke of the piston, airintroduced into the inlet 74 from a filter, such as illustrated at 82 inFIGURE 8 in open communication therewith, will open the inlet valve 76to allow air into the passage 73 and pump inlet 72. Filter 82 in theillustrated embodiment of my invention comprises an open-ended cylinderproviding a filter inlet 83 and having a filter outlet 84 comprising ahollow screw 85 threadably received in the end plate 65. Screw 85 alsoserves to attach the filter to the end plate. The filter means 87 may begauze or the like, and the side walls 11, 12, and 13 and/ or cover 15are apertured to allow air to be communicated to the filter inlet 83.

When oxygen is needed, oxygen may be introduced from the oxygen inletpipe 75 through the inlet 74, past the inlet valve 76, and into the pumpinlet 72. It is to be noted that oxygen or other gas or gas mixture sointro- 6 duced is permitted to communicate with the air inlet means.Oxygen inlet pipe 75 is extended outwardly beyond the side walls of therespirator and provided with suitable couplings to permit connection toconventional oxygen tanks.

At the end of passage 73 opposite the inlet valve 76, I have providedstill another one-Way valve assembly 90 which, in this embodiment,provides a safety valve for the maximum pressure of the pump. Thissafety valve 90 comprises a bored valve body 91, a ball 92, a valvepiston 93, and a spring 94 which serves to urge the valve piston 93 andball 92 against its seat. The compression of the spring 94 may be variedby reason of the screw type cap 95 which is threadably received over thevalve body 91, as illustrated. Thus, should the pressure in the pumpingchamber 68 exceed a value selected by the compression of safety valvespring 94, the ball 92 will be urged otf its seat, allowing the pressureto be released from valve outlet 96. The operation of the valve 90 is asthus described, even though it is in the inlet side of the pump. In thisembodiment, the valve is separate from the end plate 65, although itcould be formed as part of the plate, if thought necessary or desirable.

The pump outlet 71 is in open communication with a bore 97 which in turncommunicates with end plate outlet 98 which is in communication with ahumidifier 100, more clearly illustrated in FIGURE 6. The outlet port 98is preferably defined by a hollow screw 99 (FIG- URE 9) which serves toafiix one end of the humidifier to the end plate 65.

Humidifier 100 comprises a relatively long hollow cylinder preferably ofa length to extend from plate 65 to end wall 12 and preferablyapproximately /3 to /2 full of water, and in open communication with theplate outlet 98. Air or air-oxygen mixture from pump outlet 71 passesthrough the plate outlet 98, over the water in the humidifier 100,through the humidifier outlet 101 to which a conventional hose 102(FIGURE 1) is attached, and thence to the exhalator valve E, later to bedescribed.

As previously mentioned I have provided a novel means of filling thehumidifier 100, as well as a safety means incorporated in thehumidifier, so that a patient will not be drowned, regardless of theposition of the respirator.

As to the humidifier filling means, the end plate 65 is boredvertically, as illustrated in FIGURE 7 at 103, and is counterbored so asto be in communication with a water inlet valving means 104. Thisvalving means 104 comprises a valve body 105 threadably received in athreaded angularly disposed bore 106, and is provided with a ball valve107. The ball 107, in the embodiment illustrated, is urged against itsseat 108 by gravity, as well as by the force of the air discharging intothe humidifier 100 during the compression stroke of the piston. Whenwater is introduced into the bore 103, the weight of the Water at leastduring the suction phase of the pump, will serve to urge the ball 107off of its seat 108, so that water may enter into a flexible tube 111.This tube in turn extends into the humidifier through the humidifierinlet 98, as more clearly illustrated in FIGURE 9. I have found thatwhile the weight of the water is sufficient to lift the ball 107 off itsseat 108, the valve does not block the water tube 111, and permits thehumidifier to be filled to its proper height with water during operationof the machine.

Turning now in particular to FIGURE 2, it can be seen that thehumidifier outlet 101 is disposed at the top and in a central locationlongitudinally of the humidifier, whereby water cannot be dischargedthrough the tube 102 despite movement and/ or tilting of the respirator.

As previously mentioned, I have also provided my respirator means with ahand pump which may be used in the event there is a power failure whichstops the motor 18, or during transport of the respirator as byambulance or aircraft or to and from operating rooms 7 and the like.This hand pump is illustrated in detail in FIGURE 4 and will now bedescribed.

As can be seen in this figure, the end plate 65 is located inwardly ofand spaced from the hinged end wall 14. This wall 14 is hinged by anysuitable means to permit oscillatory movement of the wall, and the wallis provided at its swingable end with a latch, illustrated in itsentirety as 113. This latch serves normally to attach the hinged sidewall 14 to the front wall 11 and is locked by the horizontally extendinglock means 114 and the angle iron 115, suitably attached to the sidewall. Where necessary or desirable, the latch may be released andemployed as a hand grip so that the end wall 14 will serve as a umphandle. Centrally of the end wall 14, and on its inner side, there isprovided a bellows 116 aflixed at one end in sealed relationship againstthe end plate 65 on the side thereof opposite the pump chamber 68.Bellows 116 is also sealably attached to the inside surface of the endwall 14. A bolt, indicated at 117, is located centrally of the bellows116 and extends from the end wall 14 to support, at its inner end, astop cock 118, of any suitable resilient material, which fits in sealingrelationshi against the pump outlet 71 previously described.

When the latch 113 is closed, the stop cock 118 seals the pump outlet 71so that air under pressure from the pump is directed into thehumidifier. However, when the latch is unlocked and the wall 14 isoscillated, the stop cock 118 is unseated and the wall 14 serves toactuate the bellows 116. In this case, the piston 40 is stopped and thebellows performs the function of a hand pump, to force air, as well asoxygen where the latter is thought necessary or desirable, through thehumidifier 100 and into the humidifier outlet 101. It is to be notedthat since the hand pump utilizes the same pump outlet 71 it serves tofunction relative to the water inlet, the oxygen inlet, and the airinlet in a manner identical to that of the piston 40.

Turning now to the exhalator valve E, which is illustrated in detail inFIGURES and 11, it can be seen that the flexible hose 102 is providedwith a conventional coupling 130 which communicates with the base 131 ofthe valve E. The base 131 is internally axially bored, as at 132, and isprovided at one side thereof with an inlet 133 to which the coupling 130is secured. The valve includes a flat stand portion 134 so that thevalve base 131 can be held upright. At the upper end of the base 131, Ihave provided a conventional Washer 135 of any suitable material,preferably resilient, such as rubber, or rubber-like material, whichserves as a seat for valve means 136. This Washer 135 is sandwichedbetween valve base 131 and a valve chamber member 137 by a threaded capmember 138 threadably cooperating with external threads 140 on the outerperiphery of the valve chamber member 137. This threaded cap member 138has a radially inwardly extending flange 141 which cooperates with aradially outwardly extending flange 142 on the valve base 131 byoverlapping the latter. Obviously, tightening of the cap member sealablyaffixes the Washer 135 between the chamber member 137 and the valve base131. This valve chamber 137 is centrally bored as at 143 to permit thevalve means 136 to rise and fall, thereby to effect opening and closingof the port 144 defined by the washer.

At the upper end of bore 143, I have provided another washer or valveseat means 145 aflixed to the end of the chamber member 137 by a valvecap 146. Since washer 145 and valve cap means 146 are respectivelyidentical to the washer 135 and cap member 138, no further descriptionthereof is necessary.

Centrally of the chamber member 137, that is, operatively behind thevalve means 136, a threaded bore 147 is provided to receive a threadedcoupling 148 of a type similar to the coupling 130. Coupling 148 is inopen communication with still another flexible tubing 150 so that air,or air-oxygen mixture, introduced into the valve base 131 under pressurewill serve to lift the valve means 136 off its seat and raise it upagainst the upper washer 145. At that time, bore 132 is in opencommunication with the flexible hose 150 which in turn is connected tothe patient, by means of a tracheostomy tube T, or an endotracheal tubeor a face mask. The valve means 136, operating up and down in thechamber 137, provides a pressure profile for the air, or air-oxygenmixture, under pressure from either of the pumps, as will be understoodfrom the explanation hereinafter.

It is also to be noted in connection with the exhalator valve E that thevalve base 131 is provided with still another safety means, indicated at151, which comprises a bore communicating with the internal bore 132 inthe side wall of the base. This safety means 151 acts to prevent anyaccumulation of Water in the bore 132 Which might act to clog thetracheostomy tube T and drown the patient. It also acts as still anothercheck in addition to the safety means provided in the humidifier 100.

As is to be appreciated from the previous description of the pumps, theyprovide a suction stroke and a pressure stroke, so as to deliver apositive pressure (more than atmospheric pressure) and a negativepressure (less than atmospheric pressure) at the outlet thereof. Duringthe suction stroke, air or air-oxygen mixture is introduced into thepump inlet 72 from the means previously described and, on the pressurestroke, the air or gas is urged out the outlet 71. During the suctionstroke, the operation of the valve means 136 serves to prevent reverseflow of air through the humidifier and the outlet 71, and during thepressure stroke, the valve means 76 serves to prevent any air, orair-oxygen mixture, from returning to the inlet 74, as can beappreciated. Thus, normally, alternately positive and negative pressuresare created by the pump, whichever one is in operation. The pressureprofile thereby produced between the maximum positive and minimumnegative pressures, if plotted against time in a graph, would appear asa sinusoidal wave, such as illustrated in FIGURE 14 at 152. However,during the positive pressure stroke the air, or airoxygen mixture,entering into the valve base 131 is required to overcome the influenceof gravity on the valve means 136. Obviously, this requires work, whichin turn serves as a time lag betwen the opening of the valve port 144and the time pressure is first introduced into the valve base 131. Thisis represented by the vertical dotted lines at 153 in FIGURE 14. Oncethe valve seat is opened, however, by the pressure in the valve base131, the valve means is urged against the top washer to close theopening therein. Thus, air, or air-oxygen mixture is free to enter theflexible hose at a maximum positive pressure as represented at 154 inFIGURE 14. As can be appreciated, as soon as the maximum compressionstroke is completed and the suction stroke begins, again the influenceof gravity on the halving means 136 will come into play, tending to pullthe valve means 136 downwardly, closing the bore 144. Thus, as soon asthe pressure in the valve base 131 is sufficiently low so as not to beable to overcome gravity on the valving means 136 a rapid drop willoccur, as is illustrated at 155 in FIG- URE 14. Since the valve means136 closes the port 144, the negative pressure part of the pump curve,such as illustrated in FIGURE 14, is not influential on the tube 150.The pressure profile or flow of air, or air-oxygen mixture, in the tube150 thus will be a substantially squared half sine wave, such asillustrated in dotted lines in FIGURE 14.

As can be appreciated from the above explanation, the influence ofgravity on the valve member 136 of the exhalator valve E can be animportant factor in the operation of the valve. Consequently, differentvalve means may be employed depending upon the respiratory cycle to bedeveloped. In FIGURE 10, I have depicted a single steel ball in solidlines as the valve 136. If a heavier valve is required, two balls may beemployed as indicated in dotted lines. For a lighter valve, a ball oflighter material may be employed. Thus the time element between thevertical pressure profile segment 153 and 155 can be varied wherethought necessary or desirable. This forms, in connection with thevariable speed means 19, and the variable stroke means 21, still anothervariation in the control of my respirator.

Turning now to FIGURE 11, I have illustrated another valving means forthe valve E comprising a hollow tubular flanged member 156, having endflanges 157 and 158. Flanges 157 and 158 will seat against the washer135 and the upper washer 145 in a manner identical with the ball valvingmeans 136 in the previously described embodiment. Valve 156 is providedwith a screw 160 and is hollow so that additional weights could beplaced in the valve body member to regulate the time element in thepressure profile, as previously described, in lieu of the additionalball or balls in the ball valving means 136.

It is important to note, in connection with my exhalator valve E, thatthe valve is made up of interchangeable parts, preferably ofconventional washers and couplings, whereby such items as the washer 135could be replaced by the washer 145 and vice versa. Too, valve chamber137 could be reversed from the position shown and the members 138 and146 could be used interchangeably. Thus, the exhalator valve E is easyto clean, requires no special knowledge of valves, requires no specialtools, and could be put together without any special knowledge primarilybecause of the inter-changeability of the parts. This forms an importantfeature of my invention.

Having thus described all of the interrelated and Working parts of myinvention, I will now describe briefly its function and operation sothat an operator will realize the theory and practical manner of usingmy respirator.

Briefly, my respirator acts to provide hyperventilation to counteractany paradoxical respiration and overriding of any fractured ribs. It isa combination of two factors, mechanical and biochemical.

The mechanical factor is as follows:

With an uninjured chest, the bellows action of the diaphragm and theaccessory respiratory muscles work to draw and expel air to and from thelungs. The bony support of the chest wall expands and the diaphragmdescends, reducing the pressure in the chest (intrathoracic) tosubatmospheric so as to permit air at atmospheric pressure(extrathoracic) to enter the lungs. The return of the chest wall andascent of the diaphragm increases the intrathoracic pressure tosuperatmospheric, causing the air to be expelled.

When the bony support of the chest wall is broken, as illustrated as anexample in FIGURE 12, the respiratory action of the diaphragm and theaccessory respiratory muscles is markedly reduced. As the diaphragmdescends reducing intrathoracic pressure, the extrathoracic atmosphericpressure, serves partly to push in the softened chest walls as indicatedat the left in FIGURE 12, thereby compressing the lungs still further byreason of the fact that the bony support of the chest wall has beenbroken. This reduces the amount of air inspired into the lungs, if any,or in effect, enormously increases the amount of dead air space in thelungs. In active respiration with a broken chest wall, as the diaphragmascends to increase the intrathoracic pressure above atmosphericpressure extrathoracically, the broken chest Wall bulges outwardly, asillustrated at the right in FIG- URE 12, so that very little air isactually expired from the lungs. Thus, a large proportion of the airremains within the confines of the lungs and pendulates back and forthwith expiration and inspiration in a so-called paradoxical motion. Thispoor ventilation immediately leads to an inadequate absorption of oxygenand an inadequate elimination of carbon dioxide and the body responds tothese stimuli by attempting to increase the rate and depth ofrespiration. With the volume of respiration so limited an increased rateof respiration provides Vary little benefit because of the poor volumeof exchange. Most of the air motion takes place within the dead airspace which has been tremendously increased by the paradoxical motion ofthe chest Wall. To improve ventilation and relieve the hypoxia andhypercarbia that initiate a lethal chain of events, the chest wall mustbe stabilized.

Traction devices have been tried to relieve this paradoxical motion byholding out the chest walls so that a patient may adequately ventilatehimself. However, adequate stabilization of the chest walls has oftenbeen impossible because the chest wall is crushed. Too, as can beappreciated, such traction methods utilizing screws, Wires, pins, ortongs, are painful and make it difficult, if not impossible, to giveproper nursing care to the patient. Also, such methods are not availableimmediately, nor can they be brought to the scene of an accident whereproper emergency treatment may be needed.

It can also be appreciated that demand flow apparatus, relying on therequirements of the patients ability to demand are inadequate becausemany chest injuries and brain damage, etc. may block the patientsability to demand.

According to my invention, I overcome the abovestated disadvantages byforcing controlled hyperventilation of the patient. In practice, I usean uncuifed tracheostomy tube to take particular advantage of the highstroke volume of my respirator. The uncutfed tracheostomy tube permitsleakage of air through the larynx which, in turn, has other desirableeffects, namely, a safety device against excessive pressures in thelungs, and prevention of accumulation of secretions in the trachea byblowing them toward the mouth Where they are easily accessible to thenursing staff. Thus, with the uncutfed tracheostomy tube inserted asillustrated in FIGURE 1, a high amount of air is pushed into the lungsunder a pressure which exerts a general, evenly distributed outward pushof all of the softened parts holding them in their normal position, asillustrated in FIGURE 13. Any excess air flows out the mouth and/orlarynx of the patient. This is called passive mechanical inspiration.During passive exhalation by using my respirator, the intrathoracicpressure simply drops towards atmospheric pressure due to venting of thetube 150 and thus the lungs to atmosphere via the port in the valve E.Because the patient is apneic, no voluntary diaphragm action occurs bythis mechanical means, and consequently no negative intrathoracicpressure develops to produce paradoxical motion. In other words,alternating positive and subatmospheric intrathoracic pressures duringactive respiration are replaced by a fluctuating positive intrathoracicpressure, as depicted by the numerals in FIGURE 13, so that the only ribmotion is in their normal arcs while they passively ride over a cushionof air as the lungs expand and contract. All overriding and grinding ofthe broken ribs, as illustrated in FIGURE 12, is stopped by this method.

As to the biochemical factor involved in the use of my machine it hasbeen found that the cardiac output was not decreased by intermittentpositive pressure respiration, provided that the inspiratory phase andthe expiratory phase are properly controlled. In other words, normalcardiac output depends mostly on the pressure profile, in terms of thelength of the inspiratory and expiratory phases, and the meanintrathoracic pressure. A proper pressure profile allows for adequaterecovery of circulation during expiration so that the blood flow remainsnormal, even over wide ranges. This is accomplished by balancing thestroke volume and the rate of respiration against the patientstracheal-broncheal resistance and pulmonary compliance whereby a properprofile is maintained for each patient. As can be appreciated,therefore, the regulation of my respirator while in motion by the I 1proper control of the rate of reciprocation and the stroke of the pistonis very important and can give the proper profile such as illustratedtypically in FIGURE 14. Too, the balancing of the proper time elementfor the expiration and inspiration is accomplished by the valving meansin my ex-halator valve E.

With the use of the machine for hyperventilation, the carbon dioxide iswashed out of the lungs. With the drop in carbon dioxide in the alveolarair, in the blood, and in the respiratory center, active respirationceases. Hypoxia and hypercarbia, having previously aggravated pulmonaryand cerebral edema, can now be corrected and the trend reversed. Inother words, by hyperventilation the vicious cycle leading to death ibroken by adequate ventilation. The chest wall follows the passivevariations in pressure produced by my respirator, and paradoxicalmovements disappear. Briefly, it is found to be simple and safe to keepthe body in a state of slight respiratory alkalosis to render thepatient apneic so that the brains respiratory center no longer controlsthe respiration. By adjusting the stroke volume and rate of myrespirator to keep the alveolar carbon dioxide tension just at a levelto render the patient apneic, we have been able to take advantage ofthis system. No seriou deviations in blood chemistry have been foundwith prolonged mild alkalosis.

While the above description only briefly touches on the medical aspectsof the machine, it is sufficient to enable those skilled in the art tounderstand the function and operation of my machine and how it cancontribute to the treatment of severe crushing injuries in the chest bythe use of continuous hyperventilation to produce alkalotic apnea toprovide safe treatment and allow the survival of patients with seeminglyhopeles prognosis. Similarly, patients suffering from polio may besustained by the respirator of my invention, and in all cases, thepatients body is fully exposed for conventional hospital care.

While I have shown and described what I regard to be the preferredembodiments of my invention, it will be appreciated that variou changes,rearrangements and modifications may be made therein without departingfrom the scope of the invention, as defined by the appended claims.

I claim:

1. In a respirator, a pump including a reciproca'ble piston and meansfor varying the displacement of said piston, said means comprising anelongate crank arm rotatable about a transverse axis, a cam memberslidably but non-rotatably mounted on said crank arm for movementradially of said axis, said cam member being connected to said pistonfor reciprocating the same, a rotary drive member journalled on said armand operatively connected to said cam member for moving the samerelative to said arm, a drive wheel connected to said drive member andorbiting about said axis upon rotation of said arm, a pair of arcuatemembers conforming to and disposed to opposite sides of the orbital pathof movement of said Wheel, and mean for selectively moving said arcuatemembers into the path of orbital movement of said wheel for causing saidwheel to be rotated selectively in opposite directions thereby to movesaid cam member toward and away from said axis to vary the displacementof said piston during operation of the respirator.

Z. In a respirator as set forth in claim 1, resilient means normallybiasing said arcuate members to positions spaced outwardly from saidwheel, whereby the wheel normally passes between said arcuate memberswithout engaging either and the displacement of the piston is normallymaintained constant.

3. In a respirator as set forth in claim 1, means spacing said arcuatemembers at a distance from each other greater than the diameter of saidwheel whereby either one but not both of said members may be engagedwith said wheel at one time.

4. In a respirator as set forth in claim 1, the extent of each of saidarcuate members being no more than about a semi-circle whereby variationof pump displacement is intermittent to facilitate precise adjustment.

5. In a respirator, a pump including a reciprocable piston and means forvarying the displacement of said piston, said means comprising anelongate hollow crank arm having a longitudinal slot in the wallthereof, and mounted for rotation about a transverse axis, a cam memberslidably mounted in said crank formovement radially of said axis, saidcam member including an extension projecting through said slot forretaining said cam member against rotation relative to said arm, saidextension being connected to said piston for reciprocating the same, arotatable screw journalled in said arm longitudinally thereof andthreaded through said cam member for moving the same relative to saidarm, a drive wheel connected to said screw outwardly of one end of saidarm and orbiting about said axis upon rotation of said arm, a pair ofarcuate members conforming to and disposed to opposite sides of theorbital path of movement of said wheel, said arcuate members beingspaced apart a distance greater than the diameter of said wheel andnormally being positioned to accommodate free passage therebetween ofsaid wheel, and means for selectively moving said arcuate members intothe path of orbital movement of said wheel for causing said wheel to berotated selectively in opposite directions thereby to move said cammember toward and away from said axis to vary the displacement of saidpiston during operation of the respirator.

6. In a respirator, a pump including a reciprocable piston and means forvarying the rate of reciprocation and the displacement of said piston,said means comprising a rotatable drive shaft, an elongate crank armsecured to said shaft transversely thereof, a cam member slidably butnon-rotatably mounted on said crank arm for movement radially of saidshaft, said cam member being connected to said piston for reciprocatingthe same, a rotary drive member journalled on said arm and operativelyconnected to said cam member for moving the same relative to said arm, adrive wheel connected to said drive member and orbiting about said shaftupon rotation of said shaft, a pair of arcuate members conforming to anddisposed to opposite sides of the orbital path of movement of saidWheel, means for selectively moving said arcuate members into the pathof orbital movement of said wheel for causing said wheel to be rotatedselectively in opposite directions thereby to move said cam membertoward and away from said shaft to vary the displacement of said pistonduring operation of the respirator, and means independent of thelast-named means for varying the speed of rotation of said shaft duringoperation of the respirator.

7. In a respirator, a pump including a reciprocable piston and means forvarying the rate of reciprocation and the displacement of said piston,said means comprising a rotatable drive shaft, an elongate hollow crankarm secured to said shaft transversely thereof, said arm having alongitudinal slot in the wall thereof, a cam member slid-ably mounted insaid crank arm for movement radially of said shaft, said cam memberincluding an extension projecting axially through said slot forretaining said cam member against rotation relative to said arm, saidextension being connected to said piston for reciprocating the same, arotatable screw journ-alled in said arm and threaded through said cammember for moving the same relative to said arm, a drive wheel connectedto said screw outwardly of one end of said arm and orbiting about saidshaft upon rotation of said shaft, a pair of arcuate members conformingto and disposed to opposite sides of the orbital path of movement ofsaid wheel, said arcuate members being spaced apart a distance greaterthan the diameter of said wheel and normally being positioned toaccommodate free passage therebetween of said wheel, means forselectively moving said arcuate members into the path of orbitalmovement of said wheel for causing said wheel to be rotated selectivelyin opposite directions thereby to move said cam member toward and awayfrom said shaft during operation of the respirator to vary thedisplacement of said piston and the volume of respiration, a motor andvariable speed transmission for rotating said shaft, and means on saidtransmission for varying the speed of rotation of said shaft duringoperation of the respirator thereby to vary the rate of respiration.

8. In a respirator, the combination of a pump having an inlet and anoutlet, a drive for said pump, a pressure relief valve associated withthe pump for venting the same of excessive pressure, aninhalation-exhalation valve having an entrance and an outlet, atracheostomy tube connected to said valve outlet having its free endadapted for insertion into a patients trachea, outlet conduit meansextending from the pump outlet to the entrance of saidinhalation-exhalation valve, humidifying means adjacent the pump outletfor adding moisture to the air pumped through the outlet conduit meansto the inhalation-exhalation valve, and means in the outlet conduitmeans adjacent to the inhalation-exhalation valve entrance for escape ofmoisture condensing from the moistened air in said conduit meanscomprising a collection area for said moisture located below saidentrance and a port establishing communication between said collectionarea and the exterior through which moisture collecting in saidcollection area is discharged whereby the patient is protected againsthaving an excessive supply of moisture delivered to him by operation ofthe pump.

9. In a respirator, a pump including a cylinder having an end wall and apiston reciprocable in said cylinder toward and away from said wall,means for reciprocating said piston, said cylinder including an inletand an outlet each communicating with the space between said piston andsaid wall, an aperture through said wall, a hand perated pump secured tothe side of said wall opposite said piston, said hand pump communicatingwith said aperture and having as its inlet and its outlet the said inletand outlet of the first-named pump, and means releasably holding saidhand pump in an inoperative position.

10. In a respirator, a pump including a cylinder having an end wall anda piston reciprocable in said cylinder toward and away from said endwall, means for reciprocating said piston, said cylinder including aninlet and an outlet each communicating with the space between saidpiston and said end Wall, an aperture through said end wall, a bellowson the exterior of said wall in surrounding relation to said apertureand having as its inlet and its outlet the said inlet and outlet of saidpump, means for operating said bellows, means for holding the bellows ininoperative position, and a valve carried by said bellows disposed inclosing relation with said aperture upon disposition of the bellows insaid inoperative position.

11. In a respirator, a casing including spaced side Walls and an endwall movable relative to said side walls and adapted to be latched in afixed enclosing position, a pump within said casing including a cylinderhaving an end wall disposed adjacent said end wall of said casing, apiston reciprocable in said cylinder to the side of the cylinder endwall opposite said casing end wall, means for reciprocating said piston,inlet and outlet ports in said cylinder end wall, an aperture throughsaid cylinder end wall, a bellows disposed between and secured to saidend walls in surrounding relation to said aperture, and a valve membercarried by said casing end wall within said bellows, said valve memberclosing said aperture when said casing end wall is latched in said fixedposition and being spaced from said cylinder end wall and said aperturewhen said casing end wall is unlatched, said casing end wall beingreciprocable for constituting said bellows, a hand pump having as itsinlet and its outlet the said inlet and outlet of said pump.

12, An exhalation valve for respirators comprising a valve body having avertically disposed bore provided with an inlet adjacent its lower endfor connection with the respirator, a first outlet to atmosphere abovesaid inlet and a second outlet disposed between the inlet and said firstoutlet for connection with the patient, a first Valve seat over saidinlet and below said second outlet, 21 second valve seat between saidoutlets and aligned with said first valve seat, and a valve memberfreely movable between said seats adapted for alternately closing saidinlet and opening said first outlet on the suction stroke of therespirator under the pull of gravity and to open said inlet and closesaid first outlet on the pressure stroke of the respirator so as tointermittently supply fluid under positive pressure from the respiratorto the patient and in the intervals between to vent the patient toatmosphere.

13. An exhalation valve as set forth in claim 12, including means forvarying the responsiveness of said valve member to the pressurepulsations of the respirator thereby to control the respiration of thepatient.

14. In a respirator, a variable displacement piston pump having an inletand an outlet, variable speed drive means for said pump, a one-way checkvalve in the inlet of said pump, an exhalation valve spaced from saidpump and located adjacent the patient, said exhalation valve comprisinga valve body having a first inlet, a second outlet to atmosphere and anoutlet disposed between the inlet and said first outlet for connectionwith the patient, a first valve seat between said inlet and secondoutlet, a second valve seat between said outlets, and a valve membermovable between said seats, a conduit extending from the outlet of thepump to the inlet of said exhalation valve, said valve member beingresponsive to the pressure pulsations produced by said pump for movementalternately from the first valve seat to the second valve seat and fromthe second seat back to the first seat thereby to control alternatesupply of fluid from the pump to the patient and venting of the patientto atmosphere, means for varying the displacement of said pump forcontrolling the volume of respiratory fluid, means for varying the speedof said drive means for controlling the rate of respiration, and meansfor varying the responsiveness of said valve member to the pressurepulsations produced by said pump for controlling the pressure profile ofthe respiratory cycle.

15. In a respirator, a casing including side walls and an end wallhingedly connected to one of said side walls and adapted for latchingengagement with the other side wall, a pump mounted in said casinglongitudinally thereof, said pump including a cylinder having an endwall disposed adjacent the end wall of said casing, a pistonreciprocable in said cylinder to the side of the cylinder end wallopposite the casing end wall, a piston rod extending from said pistonout the opposite end of said cylinder, a motor and variable speedtransmission mounted in said casing adjacent said cylinder and includingan output shaft extending transversely of said piston rod, an elongatecrank arm secured to said shaft transversely thereof, a cam memberslidably but non-rotatably mounted on said crank arm for movementradially of said shaft and connected to said piston rod forreciprocating the piston, a rotary drive member journalled on said armand operatively connected to said cam member for moving the samerelative to said arm, a drive wheel connected to said drive member andorbiting about said shaft upon rotation of said shaft, a

pair of arcuate members conforming to and disposed to opposite sides ofthe orbital path of movement of said wheel, means for selectively movingsaid arcuate members into the path of orbital movement of said wheel forcausing said wheel to be rotated selectively in opposite directionsthereby to move said cam member toward and away from said shaft duringoperation of the respirator to vary the displacement of said piston andthereby the volume of respiratory fluid, means independent of thelast-named means for varying the speed of rotation of said shaft duringoperation of the respirator to vary the rate of respiration, said pumpincluding an inlet and an outlet communicating with the space betweensaid piston and the end wall of said cylinder, an aperture through saidcylinder end wall, a bellows disposed between and secured to said endwalls in surrounding relation to said aperture, a valve member carriedby s-aid casing end wall within said bellows, said valve memberclosing-said aperture when said casing end wall is latched to said otherside Wall, said cas-' ing end wall being oscillatable about its'hingedconnection for constituting said bellows, a hand pump having as itsinlet and its outlet the said inlet and outlet of said pump,

and said outlet to atmosphere for connectionwith the pa tient, a valveseat between said inlet and the outlet to the patient, a valve seatbetween said outlets, and a valve member movable between said seats, aconduit extending from the outlet of the humidifier to the inlet of saidexhalation valve, the valve member of said exhalation valve beingresponsive to the pressure pulsations producedlby said pump formovementialternatively betweenrth'e' 'first-; named valve seat and thesecondenamed valve seatrthereby to control-alternate supply of fluidfrom: the: pump tofthepatient and venting of the patienttoratr'nosphere' 'for Icon-1 trolling the pressure profile of therespiratoryrcycle.

16. An exhalator valve for controlling the pressure profileof gasdelivered to a patient from a respirator'pump. I

which delivers a positive pressure greater than atmosphere onitscompression stroke and anegative pressure les than atmosphere on itssuction stroke, said valve com prising a dismountableand readilycleanablebody having, a vertically disposed valve chamber provided with:an inlet} adjacent its lower end for connection to thefrespiratori pumpan outlet in the wall of. said chamber, above said; inlet for connectionto the patient and aport spaced above said outlet and venting to theatmosphere, a pair of 'vertically spaced valve seats in said chamber,the lower one being below the outlet and above the inlet and the upper;

valve seat beingabove the outlet and below'the port, and

a gravitally responsive valve closure body'freelymovable; in saidchamber between said two valve seats,-said valve closure body resting onthe lower valve seat on the suction stroke of the respirator pumpso asto vent thepatientto atmosphere through said port, being'raised off saidvalve;

seat past theoutlet to the upper valve seat under the posi-,

tive pressure of the respirator pum'pon its compression stroke to directfluid u'nder positivepres'sure to thepatient and close said port, andbeing returned to-the first valve seat past said outlet under the pullof gravity on cessation of said compression stroke, said valve memberbeing of a Weight to introduce a time lag between its opening of; theinlet to the outlet and initiation of the compression stroke of therespirator pump and to rapidly close the .inlet on cessation of saidcompression stroke whereby toproduce a fluctuating positive respirationto the patient minimally influenced by the suction stroke of therespirator pump.

17. An exhalator valve as claimed in claim 16 having a liquid collectionchamber disposedbetween the inlet and the first valve seat, and: meanscommunicating with said chamber for discharging liquid from said chamberto prevent accumulation thereof.-

a 7 References Citedby the Examiner UNITED STATES PATENTS 42,541

4/1864 Sees 137-111 908,690 1/1909 Neubert 128-145 1,099,473 6/1914Sundh 103-38 1,234,587 7/ 1917 Weatherly 230-20 1,329,137 1/1920 Oldham103-207 1,472,226 10/1923 Myers 103-207 1,786,350 12/1930 Lambert-128-29 1,846,577 2/1932 Barber 137-111 1,880,998 10/1932 Stur'tevant128-147 1,896,716 2/1933 McKesson 128-29 7/1933 I-Ieidbrink 128-296/1938 Anderson 128-29 '11/1940. Bloomheart 230-20 9/1947 vRausch 128-297 11/1952 Ra'usch 128-29 2,706,487 4/1955 .Wilson 137-102 I 2,770,23111/1956 Falk 1 128-29 FOREIGN PATENTS 799,225 8/1958 Great Britain,

GAUDET, Primary Examiner.

HAROLD. B. WHITMORE, Examiner.

15. IN A RESPIRATOR, A CASING INCLUDING SIDE WALLS AND AN END WALLHINGEDLY CONNECTED TO ONE OF SAID SIDE WALLS AND ADAPTED FOR LATCHINGENGAGEMENT WITH THE OTHER SIDE WALL, A PUMP MOUNTED IN SAID CASINGLONGITUDINALLY THEREOF, SAID PUMP INCLUDING A CYLINDER HAVING AN ENDWALL DISPOSED ADJACENT THE END WALL OF SAID CASING, A PISTONRECIPROCABLE IN SAID CYLINDER TO THE SIDE OF THE CYLINDER END WALLOPPOSITE THE CASING END WALL, A PISTON ROD EXTENDING FROM SAID PISTONOUT THE OPPOSITE END OF SAID CYLINDER, A MOTOR AND VARIABLE SPEEDTRANSMISSION MOUNTED IN SAID CASING ADJACENT SAID CYLINDER AND INCLUDINGAN OUTPUT SHAFT EXTENDING TRANSVERSELY OF SAID PISTON ROD, AN ELONGATECRANK ARM SECURED TO SAID SHAFT TRANSVERSELY THEREOF, A CAM MEMBERSLIDABLY BUT NON-ROTATABLY MOUNTED ON SAID CRANK ARM FOR MOVEMENTRADIALLY OF SAID SHAFT AND CONNECTED TO SAID PISTON ROD FORRECIPROCATING THE PISTON, A ROTARY DRIVE MEMBER JOURNALLED ON SAID ARMAND OPERATIVELY CONNECTED TO SAID CAM MEMBER FOR MOVING THE SAMERELATIVE TO SAID ARM, A DRIVE WHEEL CONNECTED TO SAID DRIVE MEMBER ANDORBITING ABOUT SAID SHAFT UPON ROTATION OF SAID SHAFT, A PAIR OF ARCUATEMEMBERS CONFORMING TO AND DISPOSED TO OPPOSITE SIDES OF THE ORBITAL PATHOF MOVEMENT OF SAID WHEEL, MEANS FOR SELECTIVELY MOVING SAID ARCUATEMEMBERS INTO THE PATH OF ORBITAL MOVEMENT OF SAID WHEEL FOR CAUSING SAIDWHEEL TO BE ROTATED SELECTIVELY IN OPPOSITE DIRECTIONS THEREBY TO MOVESAID CAM MEMBER TOWARD AND AWAY FROM SAID SHAFT DURING OPERATION OF THERESPIRATOR TO VARY THE DISPLACEMENT OF SAID PISTON AND THEREBY THEVOLUME OF RESPIRATORY FLUID, MEANS INDEPENDENT OF THE LAST-NAMED MEANSFOR VARYING THE SPEED OF ROTATION OF SAID SHAFT DURING OPERATION OF THERESPIRATOR TO VARY THE RATE OF RESPIRATION, SAID PUMP INCLUDING AN INLETAND AN OUTLET COMMUNICATING WITH THE SPACE BETWEEN SAID PISTON AND THEEND WALL OF SAID CYLINDER, AN APERTURE THROUGH SAID CYLINDER END WALL, ABELLOWS DISPOSED BETWEEN AND SECURED TO SAID END WALLS IN SURROUNDINGRELATION TO SAID APERTURE, A VALVE MEMBER CARRIED BY SAID CASING ENDWALL WITHIN SAID BELLOWS, SAID VALVE MEMBER CLOSING SAID APERTURE WHENSAID CASING END WALL IS LATCHED TO SAID OTHER SIDE WALL, SAID CASING ENDWALL BEING OSCILLATABLE ABOUT ITS HINGED CONNECTION FOR CONSTITUTINGSAID BELLOWS, A HAND PUMP HAVING AS ITS INLET AND ITS OUTLET THE SAIDINLET AND OUTLET OF SAID PUMP, A ONE-WAY CHECK VALVE IN THE INLET OFSAID PUMP, AN EXHALATION VALVE SPACED FROM SAID PUMP AND LOCATEDADJACENT THE PATIENT, SAID EXHALATION VALVE INCLUDING AN INLET, ANOUTLET TO ATMOSPHERE, AN OUTLET DISPOSED BETWEEN THE INLET AND SAIDOUTLET TO ATMOSPHERE FOR CONNECTION WITH THE PATIENT, A VALVE SEATBETWEEN SAID INLET AND THE OUTLET TO THE PATIENT, A VALVE SEAT BETWEENSAID OUTLETS, AND A VALVE MEMBER MOVABLE BETWEEN SAID SEATS, A CONDUITEXTENDING FROM THE OUTLET OF THE HUMIDIFIER TO THE INLET OF SAIDEXHALATION VALVE, THE VALVE MEMBER OF SAID EXHALATION VALVE BEINGRESPONSIVE TO THE PRESSURE PULSATIONS PRODUCED BY SAID PUMP FOR MOVEMENTALTERNATIVELY BETWEEN THE FIRSTNAMED VALVE SEAT AND THE SECOND-NAMEDVALVE SEAT THEREBY TO CONTROL ALTERNATE SUPPLY OF FLUID FROM THE PUMP TOTHE PATIENT AND VENTING OF THE PATIENT TO ATMOSPHERE FOR CONTROLLING THEPRESSURE PROFILE OF THE RESPIRATORY CYCLE.